Joanna Karczewska-Golec

Proteomic profiles and kinetics of development of bacteriophage T4 and its rI and rIII mutants in slowly growing Escherichia coli

Bacteriophage T4 survival in its natural environment requires adjustment of phage development to the slow bacterial growth rate or the initiation of mechanisms of pseudolysogeny or lysis inhibition (LIN). While phage-encoded RI and probably RIII proteins seem to be crucial players in pseudolysogeny and LIN phenomena, the identity of proteins involved in the regulation of T4 development in slowly growing bacteria has remained unknown. In this work, using a chemostat system, we studied the development of wild-type T4 (T4wt) and its rI (T4rI) and rIII (T4rIII) mutants in slowly growing bacteria, where T4 did not initiate LIN or pseudolysogeny. We determined eclipse periods, phage propagation times, latent periods and burst sizes of T4wt, T4rI and T4rIII. We also compared intracellular proteomes of slowly growing Escherichia coli infected with either T4wt or the mutants. Using two-dimensional PAGE analyses we found 18 differentially expressed proteins from lysates of infected cells. Proteins whose amounts were different in cells harbouring T4wt and the mutants are involved in processes of replication, phage-host interactions or they constitute virion components. Our data indicate that functional RI and RIII proteins - apart from their already known roles in LIN and pseudolysogeny - are also necessary for the regulation of phage T4 development in slowly growing bacteria. This regulation may be more complicated than previously anticipated, with many factors influencing T4 development in its natural habitat.

Phage-Directed Synthesis of Photoluminescent Zinc Oxide Nanoparticles under Benign Conditions

Biological systems, especially bacteriophages and peptides, are an attractive green alternative to other known methods of nanoparticle synthesis. In this work, for the first time, bacteriophages were employed to synthesize a specific peptide, capable of producing nanoparticles (NPs). Derivatives of M13 bacteriophage exposing a ZnO-binding peptide (TMGANLGLKWPV) on either pIII or pVIII phage coat protein were constructed and used as a biotemplate. The exposition of the ZnO-binding peptide, synthesized by phages during their propagation in bacteria, on M13 virions provided a groundwork for growing ZnO nanostructures. Depending on the recombinant phage type used (M13-pIII-ZnO or M13-pVIII-ZnO), well separated ZnO NPs or complex 3D structures of ZnO NPs of ca. 20-40 nm were synthesized at room temperature. The synthesized ZnO nanoparticles served as a luminescent material that emitted light near the short wavelength end of the visible region (at ca. 400 nm). The next very low intensity emission band at 530 nm demonstrated that the ZnO material obtained is characterized by a low concentration of surface defects.

Draft Genome Sequence of Flavobacterium sp. 316, a Baltic Sea Isolate Exhibiting a High Level of Resistance to Marine Stress Conditions

ABSTRACT Here, we present the draft genome sequence of Flavobacterium sp. 316, isolated from brackish water of the Gulf of Gdańsk, southern Baltic Sea. The assembly contains 3,971,755 bp in 17 scaffolds. The sequence will facilitate postgenomic studies on bacterial stress responses in the challenging habitat of the Baltic Sea.

Draft Genome Sequence of Shewanella baltica M1 Isolated from Brackish Surface Water of the Gulf of Gdańsk

ABSTRACT Here, we present the 5.168-Mbp draft genome sequence of Shewanella baltica M1, the first Shewanella strain from the Gulf of Gdańsk to have its genome sequenced and annotated. The availability of the genome sequence of strain M1 will promote further global analyses of bacterial stress responses in the unique Gulf of Gdańsk ecosystem.

115-year-old society knows how to reach young scientists: ASM Young Ambassador Program

With around 40,000 members in more than 150 countries, American Society for Microbiology (ASM) faces the challenge of meeting very diverse needs of its increasingly international members base. The newly launched ASM Young Ambassador Program seeks to aid the Society in this effort. Equipped with ASM conceptual support and financing, Young Ambassadors (YAs) design and pursue country-tailored approaches to strengthen the Societys ties with local microbiological communities. In a trans-national setting, the active presence of YAs at important scientific events, such as 16th European Congress on Biotechnology, forges new interactions between ASM and sister societies. The paper presents an overview of the Young Ambassadors-driven initiatives at both global and country levels, and explores the topic of how early-career scientists can contribute to science diplomacy and international relations.